Polyolefins are non-polar products which typically have a poor affinity with traditional materials such as for example, glass and metals in general, and are incompatible with polar synthetic polymers such as polyesters and polyamides. The ability to functionalize and therefore modify these typically chemically inert polyolefins has been highly sought after. Furthermore, the ability to efficiently and reproducibly functionalize materials such as polyethylene, polypropylene, and related copolymers with a reactive group that could be further utilized in numerous processes and end uses is particularly desirable.
Various methods to functionalize polyolefins are known. However, such methods are often characterized as tedious, time consuming, typically require air/moisture sensitive chemicals and are generally not efficient.
Examples of processes to functionalize polyolefins include the use of free radical chemistry in the reactor, such as in high pressure reactors to create ethylene-vinyl acetate type copolymers. These processes often do not provide adequate control over the number of functional groups added to the polymer.
Examples of processes to functionalize polyolefins post polymerization include grafting, wherein the polyolefin is contacted with maleic anhydride or a similar grafting material, typically in an extruder. Such processes are difficult to control and tend to cross-link the polymer, thereby changing the properties of the functionalized polymer.
Functionalization in solution is also possible, but this process is also difficult to control and tends to cross-link the polymer. Functionalization in solution also requires the additional step of solvent removal.
Accordingly, there is a need for new types of functionalized polymers and efficient, controllable, and benign methods to produce the same.